The present invention relates generally to engine oil sensors.
Many modern motor vehicles are equipped with sensors that sense the level and/or condition of the vehicle engine oil. One type of oil level/condition sensor uses multiple electrodes that are immersed in the oil. The sensor electrically monitors the oil between the electrodes and sends signals representing the oil level to a microprocessor, e.g., vehicle onboard electronics. Moreover, the sensor monitors an oil parameter, e.g., the dielectric constant, conductivity, resistivity, or viscosity, that is indicative of the condition of the oil within the oil pan and sends signal to the microprocessor representing the oil condition.
Based on the signals from the sensor, a driver of a vehicle can be warned that the level has fallen below a critical level and fresh oil must be added to the system. On the other hand, the driver can be advised to change the oil, or add chemical additives to the oil, when the condition of the oil has deteriorated below a minimum threshold. Thus, the oil is changed as dictated by the actual condition of the oil and not by a predetermined arbitrary schedule.
The present invention recognizes that when the used oil is changed, or when fresh oil or an additive is added thereto, the oil level/condition sensor and corresponding warning indicators may need to be reset. One way to reset the sensor and warning indicators employs a complicated manual reset procedure. Another method includes using the sensor to periodically check for the presence of oil within the oil pan. If the sensor indicates that the oil pan is empty, and subsequently full, it is assumed that the oil has been changed and the sensor and corresponding warning indicators are reset.
Unfortunately, it happens that oil changes can occur very rapidly and the sensor can actually miss the oil change. On the other hand, the sensor may simply not sense the oil change because the oil does not drain away from the electrodes fast enough for the sensor to recognize that the oil pan is empty.
The present invention has recognized these prior art drawbacks, and has provided the below-disclosed solutions to one or more of the prior art deficiencies.
A method for resetting a vehicle engine oil sensor includes determining whether a switch that indicates when a vehicle is being serviced is opened and if so, alerting the sensor to wake. Preferably, while the sensor is awake, an oil parameter is monitored. If the oil parameter changes a predetermined amount, the sensor is reset. In a preferred embodiment, an engine oil level/condition output device is also reset.
In one aspect of the present invention, the oil parameter is an oil level. In another aspect of the present invention, the oil parameter is an oil condition parameter, e.g., an oil dielectric value, an oil conductivity, an oil resistivity, an oil permittivity, an oil viscosity, or an oil capacitance. The oil level/condition output device is, e.g., an add-oil indicator, a change oil indicator, an oil level indicator, or an oil condition indicator. Moreover, the switch is either a hood switch that indicates when a vehicle hood is opened or an oil fill tube switch that indicates when an oil fill tube is opened.
In yet another aspect of the present invention, a system for resetting an vehicle engine oil sensor includes a vehicle having an oil pan. An oil sensor is disposed in the oil pan such that it communicates with engine oil. Moreover, the vehicle includes a switch that indicates when the vehicle is being serviced. A microprocessor is connected to the oil sensor and the switch. In this aspect of the present invention, the microprocessor includes a program for determining when the switch is opened.
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: